


Crossing the Line

by fantastic_rambles



Category: Haikyuu!!
Genre: Aftercare, Dom/sub, Established Relationship, Eventual Smut, M/M, Pampering, Rough Sex, Some Plot
Language: English
Status: In-Progress
Published: 2021-02-01
Updated: 2021-03-11
Packaged: 2021-03-12 12:53:48
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 5,044
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29135853
Author URL: https://archiveofourown.org/users/fantastic_rambles/pseuds/fantastic_rambles
Summary: Kuroo’s in a relationship with Tsukishima, but he feels that they’re in different places in terms of what they want, and thinking about it is distracting him from his work. But after talking to Kenma and getting his best friend's perspective, he decides to take the initiative and go on the attack.
Relationships: Kuroo Tetsurou/Tsukishima Kei
Comments: 11
Kudos: 90





	1. Chapter 1

"... roo, Kuroo!"

Kuroo started as he realized someone was calling his name, glancing at Kenma guiltily. The casually dressed young man stared back at him, one eyebrow arched slightly. They were sitting together in the conference room, surrounded by other members of the Japan Volleyball Association, and all eyes were on the representative of the Sports Promotion Division, making him wish he could just sink into the floor and disappear.

"As I was saying," Kenma continued, tapping on the sheaf of papers that sat in front of him, "I don't find promotional videos three and eight to be very interesting. I have provided a more detailed analysis of my findings on page eleven, along with suggested changes. I would like to see replacements for those two videos within one month's time. Would that be possible, Kuroo?"

"Uh. Yeah, that's fine," Kuroo replied, flipping through to page eleven as Kenma turned his attention to the next department. He supposed that he was lucky that it was Kenma that they were dealing with; any other sponsor would have probably taken offense to the fact that he obviously hadn't been paying attention, but Kenma really didn't care about that, as long as the work got done. Kuroo would probably still get an earful from his department head later, but it could have been a lot worse.

When the meeting finally concluded, Kenma left immediately, as he always did, and Kuroo rushed to catch up with his childhood friend, shoving the papers into his briefcase.

"Kenma!" He laid a hand on the younger man's shoulder, forcing him to stop and look back.

"What is it, Kuro?"

"Hey, you're done for the day, right? Let me treat you to dinner, as an apology for earlier."

"It's okay." Kenma shrugged off the hand, continuing to walk towards the exit, and Kuroo kept up with him, walking side-by-side.

"Please, Kenma? I want to talk to you about something, too. You're the most level-headed person I know, so I'd appreciate your perspective."

He watched as Kenma glanced at the clock hanging on the wall. 6:00. They'd run a little overtime to accommodate his schedule, since he was still in university, but nobody begrudged Kenma that time. His insights were incredibly perceptive and had contributed greatly to putting their entire program ahead of their anticipated timeline. Most of their other sponsors were satisfied to just give them money and leave the work to them, checking in on a quarterly basis, but Kenma was the same as he'd always been in high school. When he agreed to do something, he put his all into it: he might not have "guts," but he certainly did have a stubborn persistence and a determination to see things through to the end.

"I'm streaming tonight--"

"At eight, right? It won't take that long, and you've gotta eat sometime, anyway, yeah? Come on," Kuroo wheedled, and Kenma sighed. The taller man grinned broadly, recognizing his victory, and slung his arm over his former teammate's shoulders, steering him out the door.

Soon enough, they were tucked into a booth in Kuroo's favorite kappou restaurant, both of them sharing a bottle of sake as they waited for their food to come.

"So, what did you want to talk about?" Kenma asked as he accepted another pour. Kuroo hesitated for a moment, then reluctantly admitted, "Kei."

Kenma's expression didn't change, though Kuroo wasn't sure if it was because his friend had expected as much or if he simply didn't care. Well, if he was being honest, it was probably the latter. For things that didn't interest him, Kenma spent no time or energy thinking about them: when Kuroo had told him that he was dating the tall middle blocker, Kenma hadn't even turned away from his game while he was congratulating him. He never tried to pry into their relationship either, but in a way, Kuroo was grateful for his friend's simple acceptance. Though it did mean that in situations like his, he had to do almost all of the talking, since Kenma wouldn't really hold up his end of the conversation.

"There's nothing wrong with our relationship, and I know that we both like each other a lot, but... I just can't get into it lately. Our sex started out great, because we were both happy to just be able to express our love for each other, and I tried to be loving and gentle, but really, I want more than that. Sometimes, I just want to fuck him up and pound him into the sheets until he's crying. But we've been doing it this way for so long that I don't know how to bring it up, or if it'll end up scaring him away. He's never expressed any dissatisfaction with our sex life or suggested that we try anything different, but..."

He fell silent as the waitress returned with two trays of food, placing one in front of each of them, using the opportunity to drink more sake. He felt like he _should_ be more embarrassed, making a confession like this in the middle of a restaurant, but he could always be open with Kenma, bolstered by their years of friendship and old familiarity. Once the woman had left with the almost empty bottle and instructions to return with another one, Kuroo continued.

"But Kei's also the type who will just go with the flow. A bit like you, really. If he does stay and agrees to it, I won't know if it's because he actually enjoys it, or if he's just trying to make me happy. I'd hate for him to feel like he has to do something that he dislikes to satisfy me. I know that I should talk to him about this, but I don't know where to even start."

"Sounds to me like you should ask him?" Kenma commented, nibbling on a slice of fish. "Don't use leading questions, though. Something like you'd like to spice things up by trying something new, and ask him if there's anything he wants to do."

"And then what?" Kuroo demanded, acknowledging the waitress with a nod as she returned with a fresh bottle of sake.

"And then what? What do you mean?"

"What if there's nothing else he wants? Or if he's not interested in rougher sex?"

"Mmm..." Kenma paused, looking a little thoughtful. "I think you're worrying too much, Kuro. But if it comes down to it, then you'll just have to tell him."

Kuroo's eyes narrowed slightly as he stared at Kenma. It seemed like the younger man knew something, but he didn't seem inclined to share. He was far from stupid himself, but when it came to noticing things, especially about other people, Kenma could be very perceptive. Even though he had been considered a master of provocation in high school, Kuroo still had the occasional misses--like that first time with Kei--but Kenma's assertions had always been grounded firmly in reality, his fascination with the 2D world aside. When Kenma said something could be done, everyone simply believed him and acted without any hesitation or doubt.

Too casually, Kuroo leaned forward, snagging a piece of tempura from Kenma's plate and popping it into his mouth.

"Say, Kenma, how do you know so much about relationships in the first place? You've never dated anyone, at least as far as I know, and you're not an idiot like Tora who would play otomes to learn how to talk to a girl. Or a guy, I guess. Maybe it would have been better for me to have asked Akaashi for his opinion instead..."

"I know," Kenma interrupted, to Kuroo's great delight, "because I pay attention. You and Tsukishima have been together officially for almost a year now, and even before that, you kept coming back to Nekoma to practice even after you graduated whenever we had a match with Karasuno. There's no way that he doesn't know what kind of person you are by now, and you're still together. If he hasn't said anything about it, he probably also doesn't know how to bring it up. So I'm sure it'll be fine."

Kuroo laughed out loud, as boisterous as ever. Several other patrons were turning to look around while Kenma slumped down in his seat, throwing him an irritated look for drawing attention to them. But under his mirth, he felt a sense of relief at having provoked the explanation out of Kenma. It made perfect sense, and yet, he'd been worrying about it for so long. It really had been the right thing to do, getting his advice.

"Sorry, sorry," he apologized when he managed to get himself under control. "So that's how it is, then. Thanks, Kenma."

"Yeah, sure."

The rest of their meal was filled with more innocuous discussion, Kuroo asking him about his classes and his gaming career, talking about his own work in the Volleyball Association, and just catching up together. It was half past seven when Kenma glanced at his watch, his meal only half-eaten.

"It's alright, you go on ahead. Have fun," Kuroo told him as he waved the waitress back over. Kenma nodded, picking up his bag and sliding out of the booth.

"See you later, Kuro."


	2. Chapter 2

After Kuroo had finished settling the bill and getting Kenma's leftovers boxed up, he headed back to his apartment. After unlocking the door and stepping into the entrance hall, he saw a familiar pair of shoes lined up neatly with the others and grinned, stopping by the kitchen first to put away the food before going to the living room. A blond head poked over the edge of the couch, covered by a pair of headphones, and Kuroo sat down next to Kei, leaning back as he turned on his TV, just in time to catch Kenma starting his stream.  


"Hi, it's Kodzuken. Thanks for stopping by. I'm going to be continuing my Cyberpunk 2077 playthrough tonight. The background music today has been provided by Eita Semi, so please check him out."

Kuroo shook his head in wonder. It was hard to believe that such an antisocial, gloomy-looking guy could be one of the most popular streamers in Japan, as well as having a not insignificant international following. Especially considering how much he hated being at the center of attention, even now. But then again, he didn't really interact much with his viewers, just keeping them hooked based on his pure skill, so maybe it wasn't all that different from what he used to do, other than he was actually getting paid for it.

As the sounds of the game filled the room, Kuroo glanced at Kei, whose head was bent over as he worked on what looked like an assignment for one of his classes. They'd agreed early on that he wouldn't bother his boyfriend while he was working since Kei was serious about his grades, but Kuroo wasn't entirely happy with it, not when the younger man looked so cute with his brows furrowed and his mouth silently shaping the words he was reading. He wanted to push Kei back, covering those soft lips with his own and running his hand through that short, golden hair. It had been two weeks since Kei had last come over, since he'd had exams, and the fact that he could just sit there, ignoring his lover, was a little upsetting.

But only a little. After all, he'd grown up with Kenma, who was a master at ignoring and avoiding things. Still, wanting to at least be acknowledged, he reached over and tapped Kei on the shoulder, smiling when Kei turned to look at him before reaching up to pull one of the ear pieces away from his head.

"What?"

"I'm home."

Kei sighed. "Welcome back."

"Thanks. Want me to grab you something to drink?"

"Just water's fine."

"Got it." Kuroo leaned over to give the other man a quick peck on the cheek before getting up to get a glass of water for each of them. By the time he returned from the kitchen, Kei was hard at work again, so he put one of the cups down on a coaster where the blond could reach it, but would be unlikely to accidentally knock it over, and sipped at his own as he returned to watching Kenma play his game. He didn't really get the hype, but he had never really been much of a gamer in the first place, mostly just playing with Kenma. But it did provide background noise that wouldn't bother Kei, so he kept it on until Kei finally sat back with a sigh, pulling his headphones down to hang around his neck.

"Done?" Kuroo asked, covering Kei's hand with his own, and the younger man nodded, turning his hand palm-up so that they could lace their fingers together. Kuroo smirked flirtatiously, twisting their hands upward so he could press his lips to the back of his boyfriend's hand, and Kei finally smiled back, leaning in for a kiss. Kuroo was more than happy to oblige, letting their intertwined hands drop while his other hand caught Kei halfway, resting against his cheek to guide their mouths together. 

His tongue lightly slid along the crease of Kei's lips, gently teasing and asking for entrance, sliding in to meet Kei's own when his lips parted. Gradually, his hand crept higher, cradling the other man's head as Kuroo deepened the kiss further, slowly bearing down on Kei until they were both prone on the couch, lying in a tangle of legs. When they finally broke apart, both of them were panting slightly, and Kuroo felt his dick stir as he looked down at Kei, his glasses askew and his cheeks slightly flushed. He was just so hot when his usual nonchalant attitude was broken, and Kuroo wanted to take him right then and there, to watch the taller man writhe in pleasure under him. But there were more important things to take care of first.

"Have you had dinner yet?" Kuroo asked, running his hand through those short, soft locks, bracing their intertwined hands on the arm of the sofa. Kei blinked, then shook his head, trying to push himself back into a sitting position. But Kuroo held him down for a moment longer, just because he could, before shifting his weight back as well, letting his boyfriend get up.

"I was thinking that we could eat together, but you weren't here, so I decided to wait for you."

"You should have called me. If I'd known that you were here, I would have come back immediately. Do you want to go out and get something, then? Or I've got some leftovers we could heat up."

"I wanted to surprise you. I didn't realize that you were meeting up with Kozume today." Kei smirked slightly as Kuroo glanced at him, surprised. "Well, they certainly aren't yours. He's the only person you'd meet up with and leave enough leftovers that you'd take them back. They should be fine for me."

"Jeez, the two of you are too clever by half," Kuroo complained lightly, getting up and turning off the TV. Kei followed him to the kitchen, where Kuroo started up the air fryer and pulled out a pack of miso soup base, setting the electric kettle to boil. "I don't get how it is that you and Kenma can eat so little when your brains must be consuming so many nutrients. At least Kenma has the excuse that he doesn't move much, but you're still playing volleyball, too."

"Our minds are just built differently than yours," Kei retorted, taking a seat by the counter and watching Kuroo warm up his dinner. Kuroo scoffed at that as he mixed the miso soup and added some tofu and wakame, before setting the bowl down in front of the blond with a plate of sashimi before tossing the tempura into the fryer to crisp. Then, he took a seat in front of his lover, resting his chin against his palm as he leaned forward.

"Tell me this, then, Oh Intelligent One. Have you ever considered wanting to do something different in the bedroom to spice things up?" he asked, grinning as Kei suddenly choked on the soup, sputtering as he reached for a napkin. Kuroo nudged one in his direction, fighting against the urge to laugh out loud as Kei glared at him, coughing into the cloth.

"Where the hell did that come from?"

"It's a legitimate question, isn't it? I just want to make sure you're happy, Kei."

The blond looked skeptical, but Kuroo just continued to grin at him, and Kei's neutral expression reasserted itself.

"Now that you mention it, it might be interesting to top you once in a while. The former captain of Nekoma, a neko. There's something poetic there, don't you think?"

Now it was Kuroo's turn to be taken aback. Kei was always so deadpan that it was difficult to tell when he was being serious. To buy himself some time to think about the suggestion, he got up to fetch the tempura, and when he returned to the counter, he was all smiles again.

"Why not? You always look like you're enjoying yourself with my dick up your ass. I wouldn't say no to trying it at least once, see if it's as good as it looks." He watched Kei blink in surprise before a slight flush crept across his cheeks again. It was cute, how his lover could still be such a prude, which was why he would sometimes be so openly vulgar, just to see that expression. Plus, he couldn't let Kei think he'd caught him off balance, whether intentionally or not.

"I wasn't really serious," Kei mumbled, but Kuroo shrugged it off.

"I was. Up to you, though. What else?"

"Can we at least do this after I'm done eating?" Kei complained, and again, Kuroo was tempted to push him out of his comfort zone, but instead, he just smirked and nodded, watching the other man pick his way around the plate.

When he'd almost finished off everything, Kuroo asked, "Still hungry?" 

Kei shook his head, finishing off the last of it and letting Kuroo take the dirty dishes to drop into the sink. This time, when he returned to the counter, he had two crystal whiskey glasses in one hand and a decanter in the other. Sloshing a few fingers of the rich, amber liquid into each glass, he pushed one over to Kei. "Now, spill."

"Isn't it unfair if I'm the only one talking?" his boyfriend pointed out, and Kuroo shook his head.

"I'll go after. But I want to hear it from you first."

Kei sighed deeply, twisting the glass between his fingers before taking a sip, as if trying to get the courage to speak up. It was probably all the harder for him to do since he was a prude, which was why Kuroo had broken out the alcohol in the first place. He took a sip of his own, letting the sharp aroma fill his nose as the smooth, spicy liquid burned its way down his throat. It was top-shelf stuff, a gift from Kenma for his birthday, and he savored it as he waited for Kei to speak again. It took a second sip to loosen his tongue, a darker flush crawling up his face.

"You look really good in a suit, Tetsu. I wouldn't mind doing it that way, sometimes," he mumbled, and Kuroo's eyebrows lifted, intrigued. "And, uh... it's okay if you... I mean, you don't always have to be so gentle?"

"What do you mean by that?" Kuroo's smile had gained a predatory edge, and Kei's blush deepened.

"I meant what I said." He lifted his glass again, taking a too-large swallow that made him cough again, before staring at Kuroo defiantly. "What about you?"

Languidly, Kuroo got up, walking around the counter as Kei's eyes tracked his progress until he stood next to the other man, looking down at him. Kei was the one to break eye contact first, turning away from Kuroo's searing gaze, and Kuroo leaned forward, his arms on the counter trapping Kei between them.

"I'd like that too," he whispered huskily. Wide, startled eyes turned to look up at him, and Kuroo caught Kei's mouth with his own, kissing him again as he pushed him back against the counter, off his stool. His leg insinuated its way between Kei's, rubbing at the juncture until the younger man was trembling and gasping into his mouth, those long, beautiful fingers resting on his chest as if Kei wanted to push him away, but couldn't find the strength to do so. Kuroo's own hands had slipped down, off the counter, and under the edge of Kei's shirt, resting on the small of his back to pull them closer together.

He was beginning to pull the shirt off when Kei really did try to push him away, and Kuroo released him reluctantly, gently catching Kei's bottom lip between his teeth as he pulled away.

"Not here," Kei told him firmly, his face burning, and Kuroo grinned good-naturedly.

"At least not today. We'll need to come up with a system to make sure that I don't push you too far, but that can wait. Tonight, I'll just spoil you with my suit. C'mon."


	3. Chapter 3

Kuroo tugged Kei to his feet before pushing him in the direction of his bedroom, adjusting his tie. Suits, huh? That was unexpected, but not in a bad way. It was gratifying to know that Kei enjoyed his usual appearance, and clothed sex was an interesting way to start their explorations. As he passed by his dresser, he caught sight of his grin reflected in the mirror, making him smile more broadly as Kei approached the bed.

"Let me help you with that," he purred as he pushed his lover down and turned him over so that they were looking at each other. He bent over to press soft kisses against that sharply defined jaw, his lips and tongue trailing down the slender neck to nuzzle at his collarbone. Kei smelled clean, with a hint of soap, which meant he'd probably had practice today and cleaned up before he came over.

"Tetsurou, I can-" Kei protested, but Kuroo looked up, pressing a finger to the blonde's lips.

"I said I'm spoiling you tonight, right? I don't want to hear anything pass your lips besides 'Yes,' 'More,' or you telling me what you want me to do. And maybe my name. It's your reward for being honest for once."

He returned to his ministrations, reaching down to grip the hem of Kei's shirt to pull it up and off to reveal the other man's pale, toned chest. Kuroo didn't have anything against women's soft curves (and he'd even fucked a few before Kei), but seeing such a well-trained body with musculature that he could trace-and did trace-with his fingers was really something else. His hands ghosted lightly over Kei's abs, just to feel the hard muscle, as he leaned back to admire the sight before him.

"You're fucking beautiful, Kei," he growled, watching Kei turn his head aside to try to hide his embarrassed expression. Then, he bent down to add his mouth to the mix, alternately kissing the work of art before him and worrying at it lightly with his teeth to leave proof of his possession, though he remained careful to not leave the marks anywhere that would be visible above Kei's clothes. It was another one of Kei's rules, after he'd been teased relentlessly about them when his teammates had seen them once. It had bothered Kuroo at first since he'd thought that Kei might be trying to hide their relationship, but whenever they had gone out with their friends, Kei had always readily admitted that they were dating. So Kuroo had just let it go as just another one of those things.

As he teased Kei's nipples, Kei let out a groan that went straight to his dick, and Kuroo's breath hitched as he began to swell inside his pants. Given Kei's unsteady breathing, he was in the same situation, and Kuroo surged upward to capture his mouth again in a desperate, sloppy kiss. His lover finally began to relinquish his rigid self-control, draping his arms around Kuroo's neck to draw him closer as they tasted each other, their groins rubbing together in search of the friction that would get them off.

Kuroo's hands trailed lower, unbuckling Kei's belt and unzipping his pants before helping him to pull them off. At the first touch of skin on skin, Kei flinched, bucking upward into his hand, and Kuroo smiled as he broke the kiss to push himself up with his free hand so he could look down at the blond. He flicked his other hand lazily, watching Kei's expression change as the pleasure began to build. But he was surprised when Kei suddenly grabbed his tie, pulling him back down.

"Tetsu... it's fine. Want... you," his boyfriend panted, his breath hot against Kuroo's face. With his own dick straining for release, Kuroo was more than happy to comply,unbuttoning his blazer and flipping the ends out of the way. He fumbled briefly inside his dresser before pulling out a strip of condoms and lube. Impatiently, he tore at the foil with his teeth as he unbuckled his own belt, his breath coming out in a ragged sigh as he freed himself. After a few rough strokes, he slipped the condom on before turning his attention back to Kei.

While he'd prepared himself, the blond hadn't been idle. Those slim, beautiful fingers were wrapped around his own dick, flushed and slick with his pre-come. Smirking, Kuroo grabbed Kei's hand, pulling it off and raising it to his face, ignoring Kei's protests as he drew his tongue from wrist to fingertip. It was pure torture for both of them as he lavished his attention on Kei's hand, drawing each finger into his mouth and caressing it clean while breathing in the musky scent of his lover's arousal. Only when he had licked every inch of his skin did he allow Kei to pull away, blushing furiously. His own hands dropped to rest against Kei's waist, tugging the taller man's body onto his legs as he knelt on the bed before smearing the lube over himself.

"Tell me what you want, Kei," he ordered, his voice low and commanding. His erection nudged Kei's, startling a groan from his lover, and he thrust again, just to hear the noise repeated.

"Fucking... bastard..." Kei replied breathlessly, his hands fisted in the sheets.

"Oya, oya. Don't talk about yourself that way," Kuroo reprimanded him mockingly, slowly grinding against him. "Come on, tell me."

Kei's furious, hot, and needy gaze met his, and he felt himself grow even harder.

"Fuck me."

"As you wish."

He eased himself into Kei, drawing out gasps from both of them. Adjusting his grip, he pulled Kei higher as he thrust into the slick, feverish heat, aiming for the spot that would make the younger man come undone completely. But with his own legs trapped by his tailored clothes, he found that he couldn't spread them as widely as usual: even though Kei was clearly enjoying it, given the way he moaned and twisted beneath him, Kuroo's shallower thrusts were less than satisfying to him.

Growling under his breath, Kuroo backed off the end of the bed, dragging the blond with him. He saw Kei's head lift to look down at him, his expression one of startled surprise, but when Kuroo drove back in with his feet firmly anchored on the ground, that head was thrown back again with a cry that urged him onward. Grinning, Kuroo hitched Kei's legs over his arms, letting him better adjust the angle as he increased his pace. At the same time, he wrapped his fingers around Kei's dick, jerking him off in a rough, erratic rhythm.

Kuroo's own pleasure was building in a liquid heat that he tried to hold back as Kei writhed beneath him, looking hot as fuck. His smooth skin was slick with sweat, and Kuroo smirked as he watched Kei bite his own lip, trying-unsuccessfully-to stifle his cries. His moans were music to Kuroo's ears, especially since Kei's smart mouth wasn't emitting sarcastic quips for once. He enjoyed the way that the blond could play the straight man and immediately come up with a retort to any of his comments, but he loved it even more when he knew that he could silence Kei by making him feel good. With a grunt, he thrust deep into Kei, stilling as his release drowned him in blinding euphoria and left him gasping his lover's name.

Kei made a small, displeased sound as he tried to rock his body in Kuroo's grasp, pulling the older man back to reality. A few more flicks of his wrist were all that were needed for Kei to come as well, leaving him shaking in Kuroo's arms. Gently, Kuroo lowered Kei back onto the bed, letting himself slip out of the other man. After tossing the condom into the trash and cleaning them both up a little, he collapsed next to Kei.

"So, how was that?" he asked, grinning as he reached out a hand to lightly caress Kei's flushed face. But Kei didn't answer immediately, instead shifting closer so that Kuroo's arm was draped over his back. Pleased, Kuroo obeyed the unspoken request, pulling his lover into his embrace.

"Was hot," Kei mumbled, his reply muffled as he spoke into Kuroo's shoulder.

"I'm glad you think so, because you're going to be paying the dry cleaning bill."

Immediately, Kei jerked back to a sitting position, his eyes wide with outrage. "Why do I have to-"

Kuroo continued to smirk at him, and Kei's eyes narrowed. "Ass."

"I love you too." Kuroo patted the sheets next to him, and after a moment, Kei took off his glasses and placed them on the dresser before laying back down again, letting Kuroo wrap his arms around him once more.

**Notes for the Chapter:**

> So... yeah. My first legit/serious attempt at smut, and I don't like it. This has been sitting in my drafts for about a week and I've finally given up and posted it because I don't know how to make it better. -headdesk-  
> Sorry if this is disappointing. Constructive criticism very welcome!


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